Manufacture of isoprene and homolgues thereof.



HENRY STALAY ARTHUR HOLT, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY,

ASSIG-NOR TO I BADISCHE ANILIN RHINE, GERMANY, A CORPORATION.

& SODA FABRIK, OF LUDWIGSI-IAFEN-ON-THE- MANUFACTURE OF ISOPRENE ANDHOMOLOGUES THEREOF.

No Drawing.

T 0 all whom it may concern Be it known that I, HEN RY STALAY ARTHURHOLT, subject of the King of England, residing at Ludwigshafen on theRhine, Germany, have invented new and useful Improvements in theManufacture of Isoprene and Homologues Thereof, of whichthe following isa specification.

The specification of Patent No. 1,065,182 describes the manufacture ofisoprene by heating vaporized dipentene in a state of dilution.

I have now found that butadiene and members of the same homologousseries (which I hereinafter term butadiene hydrocarbons) can be obtainedin a similar manner from the mixture of dipolymerized, or more highlypolymerized, products of butadiene hydrocarbons other thancaoutchouclike matter, which mixture results as a byproduct in themanufacture of caoutchouc, or caoutchouc-like bodies, from butadienehydrocarbons. The polymerized products are preferably separated from theunaltered butadiene hydrocarbons, before being treat ed according to myinvention, and the said by-products can then be treated directly as theyare obtained by distillation With steam, or they can be previouslysubjected to fractional distillation in oacu o.

According to Harries (Anna-Zen (Zer Uhemz'e, vol. 383, page 205) thepolymerized by-products obtainable from -isop'rene consists probably ofa body C H which contains an open chain. Di-pentene, if'at all, ispresent only in minute quantities.

The following is an example of how mv invention can be carried intopractical effect but the invention is not confined to this example:Separate, from any unaltered initial Specification of Letters Patent.

Application filed .Tune 13. 1912.

Patented J an. 11, 1916. I Serial No. 703,417.

product, the oil which is obtained as a byproduct in the manufacture ofcaoutchouc from 2.3-dimethyl-1.3-butadiene, and distil the said oil withsteam. Then vaporize it and pass it at the rate of from 60 to 70 gramsper hour through a tube 0.5 meter in length containing a platinum wire 3meters in length and 0.5 millimeter in diameter, While using a currentof 400 volt-amperes and employing a pressure 01 20 millimeters. Thetemperature 700 C. The distillate consists principally of 2.3 dimethyl1.3 butadiene and small quantities of some hydrocarbons of higherboiling point.

Instead of employing electrical heating, the reaction may be carried outin a tube, or other receptacle, containing suitable material and heatedexternally.

In a similar manner, the by-products ob tained by polymerizing, tocaoutchouc, other hydrocarbons of this class, can be treated to producethe initial products.

Now what I claim is The process of producing butadiene hydrocarbons byheating in the vaporized condition, While in a state of dilution and inthe practical absence of other organic hydrocarbons, the mixture ofpolymerized products other than caoutchouc-like matter re sulting in thepolymerization of butadiene hydrocarbons.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

ARTHUR HOLT.

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